Method and Apparatus for Manufacturing Nonwoven Fabric

ABSTRACT

The invention concerns a method and apparatus for patterning a nonwoven fabric. The method according to the invention is characterized in that the web is supported in the patterning phase on a perforated cylinder to which a 3-dimensional pattern has been formed substantially without removing material (patterning cylinder) for accomplishing a corresponding 3-dimensional pattern to the nonwoven fabric. The apparatus according to the invention comprises an element supporting the web, a vacuum system and water nozzles in order to hydroentangle the fibre web or combined fibre webs. The apparatus is characterized in that the element supporting the web is of a kind of the said pattern cylinder.

The present invention concerns a method and an apparatus for patterningnonwoven fabric. More particularly, the invention concerns thepatterning of the nonwoven fabric so that during the hydroentanglement,one side of the web is supported onto an embossed, perforated plate, towhich a three dimensional pattern has been formed without removingmaterial. Patterned nonwoven fabrics can be used for example for towelsand for hygienic products as well as for sanitary applications.

By patterning of a nonwoven fabric for instance the visual properties ofthe nonwoven fabric and its use properties can be affected. Patterns canbe effected into the nonwoven fabric for instance by means of alterationof the density of the nonwoven fabric, by alteration of the grammage orby perforating. One way of patterning the nonwoven fabric is to performthe hydroentangling on a patterned hydreontanglement cylinder.

In Patent publications EP1036871 and EP1001064 it is suggested that adotted patterning or a perforation can be achieved into a nonwovenfabric by performing hydroentangling on a plastic mantle set on asupporting cylinder, said plastic mantle being equipped with pikedprotrusions being surrounded by water orifices on the plane level of themantle. With this method, however, it is not possible to accomplish acontinuous pattern, because at the protrusion of the mantle there are nowater orifices that are necessary for providing an uniform and adequatestrength to the nonwoven fabric.

The patent U.S. Pat. No. 5,674,591 discloses a nonwoven fabric beinghydroentangled on a cylinder provided with orifices for water removalbored with a laser and in addition being provided with macro sizedengraved recesses for forming a permanent, three-dimensional patterninto the nonwoven fabric, the grammage of the nonwoven fabric being atthese pattern portions the same or higher than that of the background.In said cylinder there is a micro sized surface topography patternaround the dewatering orifices, whereby the background surface of thenonwoven fabric can be made visually resembling the tricot. The patentpublication U.S. Pat. No. 5,906,786 describes the manufacturing of thiskind of a cylinder by using among others laser ablation.

In a method in accordance with a US patent application publication2002/0160681 A1, a nonwoven fabric web is patterned by hydroentanglingon a drum having as its outer structure an embossed metal wire fabric.The three-dimensional pattern of the metal wire screen is transferredonto the nonwoven fabric thus providing a nonwoven fabric havingrecesses and protrusion areas following each other. A problem with thismethod is, however, the attachment of the fibres to the pattern wirescreen, which causes the clogging of the wire, breaks in production forcleaning the wire and roughening of the nonwoven fabric to be formed.Along with the clogging, also the water removing properties of the wireare deteriorated, whereby the strength of the nonwoven fabric achievedin the hydroentangling is lowered and/or is not formed uniform. Saidfigure patterning wire always requires also a support cylinderunderneath it, in addition to a honeycomb construction.

The purpose of the present invention is to provide a method and anapparatus due to which, among others, clogging of the patterningelements when patterning the nonwoven fabric is substantiallyeliminated.

To accomplish what has been stated above, the apparatus in accordancewith the invention, is characterized in that the element supporting theweb comprises a perforated cylinder having a three dimensional patternformed onto it, substantially without removing material from it. Themethod in accordance with the present invention is characterized in thatduring the pattern forming phase the web is supported by means of aperforated cylinder having a three dimensional pattern formed onto it,substantially without removing material from it. By means of the threedimensional pattern of the pattern cylinder, a pattern or patternssubstantially corresponding to the three dimensional pattern or patternsof the pattern cylinder are accomplished to the nonwoven fabric in thehydroentanglement.

With a method and apparatus in accordance with the invention, theattachment of the fibres to the element supporting the web in thehydroentangling unit of the web-patterning phase is substantiallyeliminated. It was observed in the studies that surprisinglysubstantially no fibres get attached to the patterned element accordingto the invention supporting the web, the element being embossed to threedimensional form, during hydroentanglement and the nonwoven fabric doessubstantially not get attached to the hydroentanglement base whenremoved from the base. Thereby the need for cleaning the apparatus isdecreased, thus decreasing the number of service stops and/or breaks inproduction. The decrease in the attachment of the fibres to thehydroentangling base or the elimination thereof improves the smoothnessof the surface of the fabric to be produced. Along with the decreasedclogging of the water orifices, the effect of the hydroentangling and/orthe uniformity of the hydroentangling in connection with the patterningcan be improved. The improved hydroentangling effect means for examplethe same achieved strength of the nonwoven fabric with a smaller wateramount or with smaller pressure, or a higher strength of the nonwovenfabric with the same water amount. In addition, the element forsupporting the web when patterned, said element comprising athree-dimensional pattern and being included into an apparatus inaccordance with the invention, is simpler and less laborious tomanufacture. In addition, it is possible to improve the efficiency ofthe hydroentangling in the patterning phase, because the patterncylinder in accordance with the invention does not always require asupport cylinder under it.

The invention will be described in more detail in the following withreference to the enclosed drawings, wherein

FIG. 1 shows a continuously operating production line of nonwoven fabricfor manufacturing patterned nonwoven fabric in accordance with onepreferred embodiment of the method in accordance with the presentinvention,

FIG. 2A is a cross-sectional view of some components of one preferredembodiment of the apparatus in accordance with the invention,

FIG. 2B shows a cross-sectional view of some components of anotherpreferred embodiment of the apparatus in accordance with the invention,

FIG. 3A shows a schematic top view of an element supporting the web, inother words a pattern cylinder, according to one preferred embodimentcomprised in the apparatus in accordance with the invention, and

FIG. 3B illustrates schematically a part of the pattern cylinder of FIG.3A as a cross-sectional view.

FIG. 1 shows one continuously operating nonwoven fabric production linefor manufacturing patterned nonwoven fabric in accordance with onepreferred embodiment of the method in accordance with the presentinvention. Fibres are fed to a conveyor belt with a feeding device (1).The fibres are preferably stable fibres that have been crimped and cutfrom polymer filaments. The fibres are led to the card unit (3), forforming them mechanically into a card web. After that the card webproceeds to the first hydroentangling station (5) for prebonding. Theformed prebonded fibre web is led to another hydroentangling station (7)to be hydroentangled in an apparatus, wherein the web during thehydroentangling process is supported on a cylinder being manufactured ofa perforated plate, onto which a three-dimensional pattern has beenformed substantially without removing material, in this case byembossing. This kind of a cylinder is henceforth also referred to as apattern cylinder. The hydroentangling unit or station for patterning theweb or nonwoven fabric is in this text later also referred to as apatterning unit. After the patterning unit, the patterned nonwovenfabric is led to a drying apparatus (11) and further to be reeled with areeler (13). A production line can be provided with a plurality ofpatterning units. For manufacturing a multilayer carded web, number offibre feeding devices corresponding to the number of layers and cardingstations corresponding to the webs can be arranged for example asdescribed in the patent publication FI 20012426. As shown in thepublication FI 20012426, there can be a plurality of hydroentanglingstations arranged on the line.

FIG. 2A shows as a partial cross-sectional, schematic enlarged view somecomponents of one preferred embodiment of an apparatus, in other words,a patterning unit in accordance with the invention. The patterning unitin accordance with the invention comprises components of prior art ofthe hydroentangling unit: the pattering unit has a honeycomb structure(21), having a vacuum system (not shown) for removing the water comingfrom the water jets of the water nozzles (25) from the surface of thecylinder. The outer part of the cylinder of the patterning unit is acylinder (23) being manufactured of a perforated plate, and having athree-dimensional pattern formed substantially without removingmaterial. The pattern cylinder can be made of one or of a plurality ofperforated plates joined together in a suitable way for forming acylinder, for instance by means of a stapling arrangement or especiallyby welding. The cross-section of the orifices of the pattern cylinder isfor example substantially circular and the orifices preferably have aform of a straight cylinder. The pattern cylinder (23) is in this casepositioned directly onto the honeycomb construction. This is possiblebecause the structure of the pattern cylinder according to the inventionis rigid enough. In the embodiment in accordance with FIG. 2A, thepattern cylinder (23) is arranged to rotate along with the honeycombstructure (21). The pattern cylinder can be attached onto the honeycombstructure from the edges by means of sealing, the pattern cylinder beingfixed tightly to the honeycomb construction by raising the internal airpressure of the sealing, and made to rotate along with the honeycombconstruction. The fibre web is hydroentangled on top of the patterncylinder by means of water jets coming from the nozzles (25), thusproviding a patterned nonwoven fabric. During said patterning byhydroentanglement pattern or patterns substantially corresponding to the3-dimensional pattern or patterns of the pattern cylinder areaccomplished to the nonwoven fabric.

In one embodiment of the apparatus in accordance with the invention,shown in FIG. 2B, a support cylinder (22′) is located on the honeycombstructure (21′), said cylinder being arranged to rotate along with thehoneycomb structure (21′). The support cylinder can be fixed to thehoneycomb construction as described above in connection with the patterncylinder. The support cylinder has apertures (25′) for removing thehydroentangling water coming from the water nozzles (25′). The opensurface of the support cylinder is chosen to be as large as possible forachieving a good water removal. The size of the orifices of the supportcylinder and the open surface thereof (the portion of the perforatedarea) are preferably larger than the corresponding values of the patterncylinder. The pattern cylinder (23′) is located on the support cylinder(22′). The pattern cylinder is fixed to the support cylinder for exampleby welding, for example at the edges of the cylinder, preferably alsohere and there at the mantle of the cylinder, elsewhere than at theedges. Said support cylinder is used especially when the elongation ofthe pattern cylinder is increased due to the patterning of the patterncylinder.

A patterning unit in accordance with the invention could be installedfor example where the hydroentangling unit (7) is in the production lineshown in FIG. 1, and in that case the schematic drawings 2A and 2B wouldbe enlarged views of the point (9) shown in FIG. 1. A patterning unit inaccordance with the invention can easily be added to the process linefor patterning the nonwoven fabric.

FIG. 3A shows a part of a pattern cylinder in accordance with onepreferred embodiment, included in the apparatus in accordance with theinvention, as a top view, and FIG. 3B the same as a schematic sectionA-A. The perforated plate has patterns (32) projecting from the planelevel 31 of the plate. In this embodiment, the patterns are projectingoutwards from the plane level of the plate and from the central point ofthe cylinder outwards. The surface of the pattern cylinder 31 which hasnot been shaped by embossing, forms a plane level 31 from which surface(plane) a 3-dimensional pattern or patterns 32, accomplished to it byembossing, are protruding upwards, downwards or to both directions. Thewater nozzles 30 are arranged regularly in ternary (triangle)distribution. The pattern formed to the element supporting the web in anapparatus in accordance with the invention can have any form that can betechnically accomplished to the pattern plate. Water orifices of theplate are coinciding the patterns 32. As a result of this the fibre webis bonded efficiently also at portions where the patterns are located.The ridges of the patterns to be formed onto the plate have preferably around form and/or the peaks of the patterns can be formed even forinstance by rolling (mangling) them after being embossed. When shapingthe metal plate, the properties of the material and the way of workingof the material define the minimum possible rounding radius to be used,going below of which would damage the plate, for instance throughcracking when the pattern is being formed to the plate. In one preferredembodiment of the apparatus in accordance with the invention, thedifference in height h between the bottom and the peak of the pattern inthe perforated pattern plate is from 1 to 3 mm, especially 1.5 mm. Thepattern can be discontinuous or continuous. In one preferred embodiment,the pattern is continuous at least in one direction of the nonwoven web.The patterns to be formed by means of the apparatus and the method inaccordance with the invention can be located with even or unevendistances with regard to each other in the direction of the plane levelof the perforated plate. The distance of the patterns from each othercan be chosen freely and they can have a different height with respectto each other.

The method in accordance with the present invention for manufacturingnonwoven fabric with patterns in a continuous method comprises stagesincluding the formation of the fibre web, patterning of the nonwoven webin the hydroentangling station, in other words the patterning byhydroentanglement, and the drying of the nonwoven fabric. In onepreferred embodiment of the method in accordance with the invention, thefibre web is prebonded prior to the patterning by hydroentanglement. Inthe method in accordance with the invention, the nonwoven fabric ispatterned so that the web in the pattern hydroentanglement phase issupported onto a perforated surface, in the embodiment of FIG. 1, on aperforated cylinder, where a three dimensional pattern has been formedsubstantially without removing material. In the method in accordancewith the invention, a pattern cylinder of the apparatus in accordancewith the invention or the apparatus in accordance with the invention ispreferably used for pattern hydroentanglement. During thehydroentangling the fibres are reorganized. Immediately after thepattern hydroentanglement, before the nonwoven fabric is dried andreeled, the nonwoven fabric formed follows the form of thethree-dimensional patterning of the hydroentanglement support used forpatterning. In the final product, when unreeled, the pattern isespecially perceptible as opacity differences and/or differences in thegrammage, so that the fabric at the patterns has on average a loweropacity and/or grammage than the background. The background in thisconnection means the nonwoven fabric formed into the plane level of theplate, to which the patterns which are protruding from it, are formed.Three dimensional patterns are not accomplished to the plane level. Inone preferred embodiment the pattern is observed in the final product asdifferences in the opacity and/or grammage so that in the peaksprojecting outwards from the surface of the cylinder, the opacity and/orgrammage are at their lowest.

The element included in the apparatus in accordance with the presentinvention, said element supporting the web, is made of a perforatedmetal plate. In one embodiment it is made of a perforated metal plateready available on the market, whereby no special equipment is requiredfor perforating the material. The water used in hydroentanglement exitsthrough said orifices 30 from the surface of the pattern cylinder.Patterns or texturing is substantially not accomplished to the nonwovenfabric by perforations of the plate. According to the invention, inpatterning by hydroentanglement, substantially only pattern or patternscorresponding to the 3-dimensional pattern or patterns embossed to thepattern cylinder and protruding from it, are accomplished to thenonwoven fabric. The element for supporting the web is preferablymanufactured of acid proof or stainless metal, especially of steel. Thesurface topography of the imperforated portion of the metal plate usedfor manufacturing the pattern cylinder is substantially smooth. Thethree dimensional pattern is formed to the plate without removingmaterial, preferably by embossing. In one embodiment the threedimensionally patterned plate is made into a cylinder form by welding.

In one preferred embodiment of the element for supporting the web,included in the apparatus in accordance with the present invention, theorifices of the surface used for the forming of the pattern arepreferably arranged with a regular distribution, especially in ternary(triangle) distribution. The diameter of the orifices can range forexample from 0.2 mm to 3.0 mm and is preferably between 0.2 and 1.0 mm.In one preferred embodiment, the diameter of the orifices ranges from0.3 mm to 0.7 mm, especially 0.5 mm. The distance of the edges of theorifices from each other is at least 0.5 mm, preferably from 1 mm to 1.5mm, especially about 1.1 mm. In one embodiment the plate is perforatedwith orifices with a random distribution. The distance of the orificesfrom each other is defined for example depending on the diameter of theorifices and the perforated surface area. The portion of the orificesfrom the surface area of the pattern cylinder of the apparatus inaccordance with the invention ranges from 8% to 50%, preferably from 8%to 22%, especially from 15% to 20%. In one preferred embodiment of theinvention, the portion of the orifices in the surface ranges from 17% to20%, especially 19%.

The element supporting the web in the patterning can be manufacturedwithout complicated devices, to make the transfer to a new patternflexible.

The patterning of the nonwoven web or fabric by means of an apparatusand a method in accordance with the invention can also be implementedwithout any support cylinder (22′) by placing the pattern cylinder (23′)directly onto the honeycomb construction (21′). By means of this kind ofa patterning unit, the efficiency of the hydroentangling can beincreased, because there is no construction of a support cylinder underthe pattern cylinder that would prevent the removal of thehydroentanglement water from the surface of the cylinder.

In the method in accordance with the invention, dry web forming can beused, for example carding or air carding for forming a web. For formingof the web, also the wet web forming is possible, or for example thespunlaid technique. In the spunlaid technique, the web forming includesfibre extrusion, fibre orientation and collecting the filaments to afibre web. After the web formation the fibre web can be fed directly tothe hydroentangling station where it is patterned or preferably toprebonding before that. As a prebonding process for instance chemicalbonding, thermal bonding or mechanical bonding like hydroentanglementcan be used. In one preferred embodiment of the method in accordancewith the invention, solely hydroentangling is used as a prebondingprocess. Hydroentangling for prebonding the fibre web is preferably notperformed in the same hydroentangling unit as the hydroentangling forpatterning the nonwoven fabric. In one preferred embodiment of theinvention the fibre web is formed of stable fibres by carding.

The method in accordance with the invention is suitable for patterningof nonwoven fabrics both having a monolayer construction and multilayerconstruction. According to one embodiment of the invention, a patternednonwoven fabric having a multilayer construction can be made by addingto the production line of the fabric one or a plurality of fibre webforming stations, like for example a carding station, in order to form apatterned multilayer construction in a continuous process. In accordancewith another embodiment, the patterned multilayer construction can beimplemented also by bringing to the process one or a plurality ofseparately (off-line) formed and/or prebonded fibre web(s). The fibrewebs (layers) forming the multilayer nonwoven fabric or a part of themcan be combined prior to the patterning by hydroentanglement, forexample in a hydroentangling unit before the patterning byhydroentanglement, or separate fibre webs can be brought directly to thepatterning unit, whereby the fibre webs are combined and the combinedfibre webs are patterned in the same stage of the process.

For example polyolefin fibres can be used in the method in accordancewith the invention, like polythylene of polypropylene fibres, polyesterfibres, viscose and pulp fibres and different mixtures of these fibres.The mass proportions of polypropylene or polyester: viscose vary,especially at least in one fibre web, preferably ranging from 10:90 to90:10, especially from 20:80 to 80:20. In one preferred embodiment saidmass proportion ranges from 30:70 to 70:30, especially from 30:70 to40:60. The fibre fineness of the fibres used in the method in accordancewith the invention, preferably ranges from 1 to 3.3 dtex, especiallyadvantageously 1.7 dtex. In one preferred embodiment of the method inaccordance with the invention, only polypropylene/viscose fibre mixtureis used, and in another preferred embodiment only polyester/viscosemixture of fibres is used at least in one fibre web, preferably inproportions mentioned above. Nonwoven fabrics manufactured using themethod in accordance with the invention, especially by using theabove-mentioned fibres, are especially suitable for use in wipe andhygienic applications, as well as in sanitary applications, likesurgical gauzes.

In the following, the invention will be illustrated in more detail bymeans of an example.

EXAMPLE Sample Preparation

Nonwoven fabric was manufactured from a mixture of polyester/viscosefibres (mass proportion 33/67). The fineness of the fibres was 1.7 dtex.Stable fibres having a fibre length of 40 mm were used. The grammage ofthe nonwoven fabric was 55 g/m². The nonwoven fabric was manufactured ona nonwoven fabric line as shown in FIG. 1, where the fibre web wasformed by carding, and where two hydroentanglement units were used. Thepatterning of the nonwoven fabric was performed after that byhydroentangling by means of water jets having a diameter of 0.12 mm anda jet density of 40/inch. The hydroentangling was performed twice, usinga pressure of 80 bars. The hydroentangling base was a smooth metal wirescreen, with 75 mesh, made of acid proof steel and one embossed into athree-dimensional form, and a smooth perforated metal plate made of acidproof steel and one embossed into a three-dimensional form. The metalplate had orifices of 0.5 mm in triangle (ternary) distribution(distance between the orifices 1.09 mm) and the open surface area, inother words the surface of the perforated portion of the plate was 19%.The metal plate had a thickness of 0.4 mm and the orifices had a form ofa straight cylinder.

Detachment Test

The pulling test was used for testing the detachment of the nonwovenfabric from the base used to support it during the hydroentanglement.

The force required for removing the nonwoven fabric from thehydroentanglement base was measured with pulling device ZwickBZ2.5/TN1S. A sample having a width of 50 mm was used for the pullingtest. The sample was in a state as after the hydroentangling on thehydroentanglement base. The hydroentanglement base was located on thelower jaw of the pulling device and was kept immovable at the lower jaw.The fabric sample was slightly detached from the needling base andattached to the upper jaw of the pulling device. A measuring transducerof 10 N was used in the pulling device, whereby a measuring result couldbe received from the pulling device when the pulling force of 0.1 N wasexceeded. The width of the jaw was 50 mm. The force required fordetaching (removing) the sample from the base was measured for a lengthof 50 mm. The results were recorded from removal length of 15 mm and 50mm. The pulling interspace was 50 mm and the pulling angle was not lowerthan 90 degrees. The pulling speed was 100 mm/min and the pullingdirection was the machine direction. The results were received as anaverage force required for removal for 15 mm and 50 mm. Four parallelsamples were used in measurements. In case after two measurements nomeasuring result was obtained, in other words, if the required pullingforce did not exceed 0.1 N, the testing of the sample was not continued.

Non-Patterned Hydroentanglement Base

The force required for removing the sample from the base could not bemeasured, when a smooth (flat) wire screen was used as ahydroentanglement base, because the sample had not got attached to thebase during the hydroentanglement. Also, when a smooth (flat) perforatedplate was used as a hydroentanglement base, no result could be receivedwith the pulling device. Visual inspection showed no fibres attached tothe base. The structure of the unpatterned hydroentanglement base had noinfluence on the adhesion of the nonwoven fabric to the base.

Patterned Hydroentanglement Base (Comprising a Three-DimensionalPattern)

Forces from four measurements required for attachment of a sample incases, where a metal wire screen embossed into a three-dimensionalpattern was used as a hydroentanglement base, are shown in Table 1, saidresults being received from four measurements

TABLE 1 Average of detachment force at Pulling detachment length of 15and 50 mm direction Sample No N MD 1 0.15 MD 2 0.15 MD 3 0.17 MD 4 0.26

A substantial amount of fibres had adhered into the metal wire screen inthe detachment (removal) stage, seen by the visual inspection.

It was observed that the embossing of the metal wire screen intothree-dimensional form causes the movement of the wires and theoverlapping of them so that there are gaps formed between the wires intothe surface of the wire, so that the fibres get easily stuck into them.In the hydroentanglement, the water jets push the fibres to the gapsbetween the wires, which makes the removal of the fabric from the wiredifficult and fibres get attached to the hydroentanglement base.

When a perforated metal plate embossed into a three-dimensional form wasused as a hydroentanglement base, it was not possible to measure theforce required for detachment. Surprisingly, the formed patternednonwoven fabric did not stick to the base during the hydroentanglement.No fibres were either seen by the visual inspection been attached tothis kind of a patterned, perforated metal plate.

The present invention concerns a method and an apparatus for patterningnonwoven fabric. More particularly, the invention concerns thepatterning of the nonwoven fabric so that during the hydroentanglement,one side of the web is supported onto an embossed, perforated plate, towhich a three dimensional pattern has been formed without removingmaterial. Patterned nonwoven fabrics can be used for example for towelsand for hygienic products as well as for sanitary applications.

By patterning of a nonwoven fabric for instance the visual properties ofthe nonwoven fabric and its use properties can be affected. Patterns canbe effected into the nonwoven fabric for instance by means of alterationof the density of the nonwoven fabric, by alteration of the grammage orby perforating. One way of patterning the nonwoven fabric is to performthe hydroentangling on a patterned hydreontanglement cylinder.

In Patent publications EP1036871 and EP1001064 it is suggested that adotted patterning or a perforation can be achieved into a nonwovenfabric by performing hydroentangling on a plastic mantle set on asupporting cylinder, said plastic mantle being equipped with pikedprotrusions being surrounded by water orifices on the plane level of themantle. With this method, however, it is not possible to accomplish acontinuous pattern, because at the protrusion of the mantle there are nowater orifices that are necessary for providing an uniform and adequatestrength to the nonwoven fabric.

The patent U.S. Pat. No. 5,674,591 discloses a nonwoven fabric beinghydroentangled on a cylinder provided with orifices for water removalbored with a laser and in addition being provided with macro sizedengraved recesses for forming a permanent, three-dimensional patterninto the nonwoven fabric, the grammage of the nonwoven fabric being atthese pattern portions the same or higher than that of the background.In said cylinder there is a micro sized surface topography patternaround the dewatering orifices, whereby the background surface of thenonwoven fabric can be made visually resembling the tricot. The patentpublication U.S. Pat. No. 5,906,786 describes the manufacturing of thiskind of a cylinder by using among others laser ablation.

In a method in accordance with a US patent application publication2002/0160681 A1, a nonwoven fabric web is patterned by hydroentanglingon a drum having as its outer structure an embossed metal wire fabric.The three-dimensional pattern of the metal wire screen is transferredonto the nonwoven fabric thus providing a nonwoven fabric havingrecesses and protrusion areas following each other. A problem with thismethod is, however, the attachment of the fibres to the pattern wirescreen, which causes the clogging of the wire, breaks in production forcleaning the wire and roughening of the nonwoven fabric to be formed.Along with the clogging, also the water removing properties of the wireare deteriorated, whereby the strength of the nonwoven fabric achievedin the hydroentangling is lowered and/or is not formed uniform. Saidfigure patterning wire always requires also a support cylinderunderneath it, in addition to a honeycomb construction.

The purpose of the present invention is to provide a method and anapparatus due to which, among others, clogging of the patterningelements when patterning the nonwoven fabric is substantiallyeliminated.

To accomplish what has been stated above, the apparatus in accordancewith the invention, is characterized in that the element supporting theweb comprises a perforated cylinder having a three dimensional patternformed onto it, substantially without removing material from it. Themethod in accordance with the present invention is characterized in thatduring the pattern forming phase the web is supported by means of aperforated cylinder having a three dimensional pattern formed onto it,substantially without removing material from it. By means of the threedimensional pattern of the pattern cylinder, a pattern or patternssubstantially corresponding to the three dimensional pattern or patternsof the pattern cylinder are accomplished to the nonwoven fabric in thehydroentanglement.

With a method and apparatus in accordance with the invention, theattachment of the fibres to the element supporting the web in thehydroentangling unit of the web-patterning phase is substantiallyeliminated. It was observed in the studies that surprisinglysubstantially no fibres get attached to the patterned element accordingto the invention supporting the web, the element being embossed to threedimensional form, during hydroentanglement and the nonwoven fabric doessubstantially not get attached to the hydroentanglement base whenremoved from the base. Thereby the need for cleaning the apparatus isdecreased, thus decreasing the number of service stops and/or breaks inproduction. The decrease in the attachment of the fibres to thehydroentangling base or the elimination thereof improves the smoothnessof the surface of the fabric to be produced. Along with the decreasedclogging of the water orifices, the effect of the hydroentangling and/orthe uniformity of the hydroentangling in connection with the patterningcan be improved. The improved hydroentangling effect means for examplethe same achieved strength of the nonwoven fabric with a smaller wateramount or with smaller pressure, or a higher strength of the nonwovenfabric with the same water amount. In addition, the element forsupporting the web when patterned, said element comprising athree-dimensional pattern and being included into an apparatus inaccordance with the invention, is simpler and less laborious tomanufacture. In addition, it is possible to improve the efficiency ofthe hydroentangling in the patterning phase, because the patterncylinder in accordance with the invention does not always require asupport cylinder under it.

The invention will be described in more detail in the following withreference to the enclosed drawings, wherein

FIG. 1 shows a continuously operating production line of nonwoven fabricfor manufacturing patterned nonwoven fabric in accordance with onepreferred embodiment of the method in accordance with the presentinvention,

FIG. 2A is a cross-sectional view of some components of one preferredembodiment of the apparatus in accordance with the invention,

FIG. 2B shows a cross-sectional view of some components of anotherpreferred embodiment of the apparatus in accordance with the invention,

FIG. 3A shows a schematic top view of an element supporting the web, inother words a pattern cylinder, according to one preferred embodimentcomprised in the apparatus in accordance with the invention, and

FIG. 3B illustrates schematically a part of the pattern cylinder of FIG.3A as a cross-sectional view.

FIG. 1 shows one continuously operating nonwoven fabric production linefor manufacturing patterned nonwoven fabric in accordance with onepreferred embodiment of the method in accordance with the presentinvention. Fibres are fed to a conveyor belt with a feeding device (1).The fibres are preferably stable fibres that have been crimped and cutfrom polymer filaments. The fibres are led to the card unit (3), forforming them mechanically into a card web. After that the card webproceeds to the first hydroentangling station (5) for prebonding. Theformed prebonded fibre web is led to another hydroentangling station (7)to be hydroentangled in an apparatus, wherein the web during thehydroentangling process is supported on a cylinder being manufactured ofa perforated plate, onto which a three-dimensional pattern has beenformed substantially without removing material, in this case byembossing. This kind of a cylinder is henceforth also referred to as apattern cylinder. The hydroentangling unit or station for patterning theweb or nonwoven fabric is in this text later also referred to as apatterning unit. After the patterning unit, the patterned nonwovenfabric is led to a drying apparatus (11) and further to be reeled with areeler (13). A production line can be provided with a plurality ofpatterning units. For manufacturing a multilayer carded web, number offibre feeding devices corresponding to the number of layers and cardingstations corresponding to the webs can be arranged for example asdescribed in the patent publication FI 20012426. As shown in thepublication FI 20012426, there can be a plurality of hydroentanglingstations arranged on the line.

FIG. 2A shows as a partial cross-sectional, schematic enlarged view somecomponents of one preferred embodiment of an apparatus, in other words,a patterning unit in accordance with the invention. The patterning unitin accordance with the invention comprises components of prior art ofthe hydroentangling unit: the pattering unit has a honeycomb structure(21), having a vacuum system (not shown) for removing the water comingfrom the water jets of the water nozzles (25) from the surface of thecylinder. The outer part of the cylinder of the patterning unit is acylinder (23) being manufactured of a perforated plate, and having athree-dimensional pattern formed substantially without removingmaterial. The pattern cylinder can be made of one or of a plurality ofperforated plates joined together in a suitable way for forming acylinder, for instance by means of a stapling arrangement or especiallyby welding. The cross-section of the orifices of the pattern cylinder isfor example substantially circular and the orifices preferably have aform of a straight cylinder. The pattern cylinder (23) is in this casepositioned directly onto the honeycomb construction. This is possiblebecause the structure of the pattern cylinder according to the inventionis rigid enough. In the embodiment in accordance with FIG. 2A, thepattern cylinder (23) is arranged to rotate along with the honeycombstructure (21). The pattern cylinder can be attached onto the honeycombstructure from the edges by means of sealing, the pattern cylinder beingfixed tightly to the honeycomb construction by raising the internal airpressure of the sealing, and made to rotate along with the honeycombconstruction. The fibre web is hydroentangled on top of the patterncylinder by means of water jets coming from the nozzles (25), thusproviding a patterned nonwoven fabric. During said patterning byhydroentanglement pattern or patterns substantially corresponding to the3-dimensional pattern or patterns of the pattern cylinder areaccomplished to the nonwoven fabric.

In one embodiment of the apparatus in accordance with the invention,shown in FIG. 2B, a support cylinder (22′) is located on the honeycombstructure (21′), said cylinder being arranged to rotate along with thehoneycomb structure (21′). The support cylinder can be fixed to thehoneycomb construction as described above in connection with the patterncylinder. The support cylinder has apertures (25′) for removing thehydroentangling water coming from the water nozzles (25′). The opensurface of the support cylinder is chosen to be as large as possible forachieving a good water removal. The size of the orifices of the supportcylinder and the open surface thereof (the portion of the perforatedarea) are preferably larger than the corresponding values of the patterncylinder. The pattern cylinder (23′) is located on the support cylinder(22′). The pattern cylinder is fixed to the support cylinder for exampleby welding, for example at the edges of the cylinder, preferably alsohere and there at the mantle of the cylinder, elsewhere than at theedges. Said support cylinder is used especially when the elongation ofthe pattern cylinder is increased due to the patterning of the patterncylinder.

A patterning unit in accordance with the invention could be installedfor example where the hydroentangling unit (7) is in the production lineshown in FIG. 1, and in that case the schematic drawings 2A and 2B wouldbe enlarged views of the point (9) shown in FIG. 1. A patterning unit inaccordance with the invention can easily be added to the process linefor patterning the nonwoven fabric.

FIG. 3A shows a part of a pattern cylinder in accordance with onepreferred embodiment, included in the apparatus in accordance with theinvention, as a top view, and FIG. 3B the same as a schematic sectionA-A. The perforated plate has patterns (32) projecting from the planelevel 31 of the plate. In this embodiment, the patterns are projectingoutwards from the plane level of the plate and from the central point ofthe cylinder outwards. The surface of the pattern cylinder 31 which hasnot been shaped by embossing, forms a plane level 31 from which surface(plane) a 3-dimensional pattern or patterns 32, accomplished to it byembossing, are protruding upwards, downwards or to both directions. Thewater nozzles 30 are arranged regularly in ternary (triangle)distribution. The pattern formed to the element supporting the web in anapparatus in accordance with the invention can have any form that can betechnically accomplished to the pattern plate. Water orifices of theplate are coinciding the patterns 32. As a result of this the fibre webis bonded efficiently also at portions where the patterns are located.The ridges of the patterns to be formed onto the plate have preferably around form and/or the peaks of the patterns can be formed even forinstance by rolling (mangling) them after being embossed. When shapingthe metal plate, the properties of the material and the way of workingof the material define the minimum possible rounding radius to be used,going below of which would damage the plate, for instance throughcracking when the pattern is being formed to the plate. In one preferredembodiment of the apparatus in accordance with the invention, thedifference in height h between the bottom and the peak of the pattern inthe perforated pattern plate is from 1 to 3 mm, especially 1.5 mm. Thepattern can be discontinuous or continuous. In one preferred embodiment,the pattern is continuous at least in one direction of the nonwoven web.The patterns to be formed by means of the apparatus and the method inaccordance with the invention can be located with even or unevendistances with regard to each other in the direction of the plane levelof the perforated plate. The distance of the patterns from each othercan be chosen freely and they can have a different height with respectto each other.

The method in accordance with the present invention for manufacturingnonwoven fabric with patterns in a continuous method comprises stagesincluding the formation of the fibre web, patterning of the nonwoven webin the hydroentangling station, in other words the patterning byhydroentanglement, and the drying of the nonwoven fabric. In onepreferred embodiment of the method in accordance with the invention, thefibre web is prebonded prior to the patterning by hydroentanglement. Inthe method in accordance with the invention, the nonwoven fabric ispatterned so that the web in the pattern hydroentanglement phase issupported onto a perforated surface, in the embodiment of FIG. 1, on aperforated cylinder, where a three dimensional pattern has been formedsubstantially without removing material. In the method in accordancewith the invention, a pattern cylinder of the apparatus in accordancewith the invention or the apparatus in accordance with the invention ispreferably used for pattern hydroentanglement. During thehydroentangling the fibres are reorganized. Immediately after thepattern hydroentanglement, before the nonwoven fabric is dried andreeled, the nonwoven fabric formed follows the form of thethree-dimensional patterning of the hydroentanglement support used forpatterning. In the final product, when unreeled, the pattern isespecially perceptible as opacity differences and/or differences in thegrammage, so that the fabric at the patterns has on average a loweropacity and/or grammage than the background. The background in thisconnection means the nonwoven fabric formed into the plane level of theplate, to which the patterns which are protruding from it, are formed.Three dimensional patterns are not accomplished to the plane level. Inone preferred embodiment the pattern is observed in the final product asdifferences in the opacity and/or grammage so that in the peaksprojecting outwards from the surface of the cylinder, the opacity and/orgrammage are at their lowest.

The element included in the apparatus in accordance with the presentinvention, said element supporting the web, is made of a perforatedmetal plate. In one embodiment it is made of a perforated metal plateready available on the market, whereby no special equipment is requiredfor perforating the material. The water used in hydroentanglement exitsthrough said orifices 30 from the surface of the pattern cylinder.Patterns or texturing is substantially not accomplished to the nonwovenfabric by perforations of the plate. According to the invention, inpatterning by hydroentanglement, substantially only pattern or patternscorresponding to the 3-dimensional pattern or patterns embossed to thepattern cylinder and protruding from it, are accomplished to thenonwoven fabric. The element for supporting the web is preferablymanufactured of acid proof or stainless metal, especially of steel. Thesurface topography of the imperforated portion of the metal plate usedfor manufacturing the pattern cylinder is substantially smooth. Thethree dimensional pattern is formed to the plate without removingmaterial, preferably by embossing. In one embodiment the threedimensionally patterned plate is made into a cylinder form by welding.

In one preferred embodiment of the element for supporting the web,included in the apparatus in accordance with the present invention, theorifices of the surface used for the forming of the pattern arepreferably arranged with a regular distribution, especially in ternary(triangle) distribution. The diameter of the orifices can range forexample from 0.2 mm to 3.0 mm and is preferably between 0.2 and 1.0 mm.In one preferred embodiment, the diameter of the orifices ranges from0.3 mm to 0.7 mm, especially 0.5 mm. The distance of the edges of theorifices from each other is at least 0.5 mm, preferably from 1 mm to 1.5mm, especially about 1.1 mm. In one embodiment the plate is perforatedwith orifices with a random distribution. The distance of the orificesfrom each other is defined for example depending on the diameter of theorifices and the perforated surface area. The portion of the orificesfrom the surface area of the pattern cylinder of the apparatus inaccordance with the invention ranges from 8% to 50%, preferably from 8%to 22%, especially from 15% to 20%. In one preferred embodiment of theinvention, the portion of the orifices in the surface ranges from 17% to20%, especially 19%.

The element supporting the web in the patterning can be manufacturedwithout complicated devices, to make the transfer to a new patternflexible.

The patterning of the nonwoven web or fabric by means of an apparatusand a method in accordance with the invention can also be implementedwithout any support cylinder (22′) by placing the pattern cylinder (23′)directly onto the honeycomb construction (21′). By means of this kind ofa patterning unit, the efficiency of the hydroentangling can beincreased, because there is no construction of a support cylinder underthe pattern cylinder that would prevent the removal of thehydroentanglement water from the surface of the cylinder.

In the method in accordance with the invention, dry web forming can beused, for example carding or air carding for forming a web. For formingof the web, also the wet web forming is possible, or for example thespunlaid technique. In the spunlaid technique, the web forming includesfibre extrusion, fibre orientation and collecting the filaments to afibre web. After the web formation the fibre web can be fed directly tothe hydroentangling station where it is patterned or preferably toprebonding before that. As a prebonding process for instance chemicalbonding, thermal bonding or mechanical bonding like hydroentanglementcan be used. In one preferred embodiment of the method in accordancewith the invention, solely hydroentangling is used as a prebondingprocess. Hydroentangling for prebonding the fibre web is preferably notperformed in the same hydroentangling unit as the hydroentangling forpatterning the nonwoven fabric. In one preferred embodiment of theinvention the fibre web is formed of stable fibres by carding.

The method in accordance with the invention is suitable for patterningof nonwoven fabrics both having a monolayer construction and multilayerconstruction. According to one embodiment of the invention, a patternednonwoven fabric having a multilayer construction can be made by addingto the production line of the fabric one or a plurality of fibre webforming stations, like for example a carding station, in order to form apatterned multilayer construction in a continuous process. In accordancewith another embodiment, the patterned multilayer construction can beimplemented also by bringing to the process one or a plurality ofseparately (off-line) formed and/or prebonded fibre web(s). The fibrewebs (layers) forming the multilayer nonwoven fabric or a part of themcan be combined prior to the patterning by hydroentanglement, forexample in a hydroentangling unit before the patterning byhydroentanglement, or separate fibre webs can be brought directly to thepatterning unit, whereby the fibre webs are combined and the combinedfibre webs are patterned in the same stage of the process.

For example polyolefin fibres can be used in the method in accordancewith the invention, like polythylene of polypropylene fibres, polyesterfibres, viscose and pulp fibres and different mixtures of these fibres.The mass proportions of polypropylene or polyester: viscose vary,especially at least in one fibre web, preferably ranging from 10:90 to90:10, especially from 20:80 to 80:20. In one preferred embodiment saidmass proportion ranges from 30:70 to 70:30, especially from 30:70 to40:60. The fibre fineness of the fibres used in the method in accordancewith the invention, preferably ranges from 1 to 3.3 dtex, especiallyadvantageously 1.7 dtex. In one preferred embodiment of the method inaccordance with the invention, only polypropylene/viscose fibre mixtureis used, and in another preferred embodiment only polyester/viscosemixture of fibres is used at least in one fibre web, preferably inproportions mentioned above. Nonwoven fabrics manufactured using themethod in accordance with the invention, especially by using theabove-mentioned fibres, are especially suitable for use in wipe andhygienic applications, as well as in sanitary applications, likesurgical gauzes.

In the following, the invention will be illustrated in more detail bymeans of an example.

Example Sample Preparation

Nonwoven fabric was manufactured from a mixture of polyester/viscosefibres (mass proportion 33/67). The fineness of the fibres was 1.7 dtex.Stable fibres having a fibre length of 40 mm were used. The grammage ofthe nonwoven fabric was 55 g/m². The nonwoven fabric was manufactured ona nonwoven fabric line as shown in FIG. 1, where the fibre web wasformed by carding, and where two hydroentanglement units were used. Thepatterning of the nonwoven fabric was performed after that byhydroentangling by means of water jets having a diameter of 0.12 mm anda jet density of 40/inch. The hydroentangling was performed twice, usinga pressure of 80 bars. The hydroentangling base was a smooth metal wirescreen, with 75 mesh, made of acid proof steel and one embossed into athree-dimensional form, and a smooth perforated metal plate made of acidproof steel and one embossed into a three-dimensional form. The metalplate had orifices of 0.5 mm in triangle (ternary) distribution(distance between the orifices 1.09 mm) and the open surface area, inother words the surface of the perforated portion of the plate was 19%.The metal plate had a thickness of 0.4 mm and the orifices had a form ofa straight cylinder.

Detachment Test

The pulling test was used for testing the detachment of the nonwovenfabric from the base used to support it during the hydroentanglement.

The force required for removing the nonwoven fabric from thehydroentanglement base was measured with pulling device ZwickBZ2.5/TN1S. A sample having a width of 50 mm was used for the pullingtest. The sample was in a state as after the hydroentangling on thehydroentanglement base. The hydroentanglement base was located on thelower jaw of the pulling device and was kept immovable at the lower jaw.The fabric sample was slightly detached from the needling base andattached to the upper jaw of the pulling device. A measuring transducerof 10 N was used in the pulling device, whereby a measuring result couldbe received from the pulling device when the pulling force of 0.1 N wasexceeded. The width of the jaw was 50 mm. The force required fordetaching (removing) the sample from the base was measured for a lengthof 50 mm. The results were recorded from removal length of 15 mm and 50mm. The pulling interspace was 50 mm and the pulling angle was not lowerthan 90 degrees. The pulling speed was 100 mm/min and the pullingdirection was the machine direction. The results were received as anaverage force required for removal for 15 mm and 50 mm. Four parallelsamples were used in measurements. In case after two measurements nomeasuring result was obtained, in other words, if the required pullingforce did not exceed 0.1 N, the testing of the sample was not continued.

Non-Patterned Hydroentanglement Base

The force required for removing the sample from the base could not bemeasured, when a smooth (flat) wire screen was used as ahydroentanglement base, because the sample had not got attached to thebase during the hydroentanglement. Also, when a smooth (flat) perforatedplate was used as a hydroentanglement base, no result could be receivedwith the pulling device. Visual inspection showed no fibres attached tothe base. The structure of the unpatterned hydroentanglement base had noinfluence on the adhesion of the nonwoven fabric to the base.

Patterned Hydroentanglement Base (Comprising A Three-DimensionalPattern)

Forces from four measurements required for attachment of a sample incases, where a metal wire screen embossed into a three-dimensionalpattern was used as a hydroentanglement base, are shown in Table 1, saidresults being received from four measurements

TABLE 1 Average of detachment force at Pulling detachment length of 15and 50 mm direction Sample No N MD 1 0.15 MD 2 0.15 MD 3 0.17 MD 4 0.26

A substantial amount of fibres had adhered into the metal wire screen inthe detachment (removal) stage, seen by the visual inspection.

It was observed that the embossing of the metal wire screen intothree-dimensional form causes the movement of the wires and theoverlapping of them so that there are gaps formed between the wires intothe surface of the wire, so that the fibres get easily stuck into them.In the hydroentanglement, the water jets push the fibres to the gapsbetween the wires, which makes the removal of the fabric from the wiredifficult and fibres get attached to the hydroentanglement base.

When a perforated metal plate embossed into a three-dimensional form wasused as a hydroentanglement base, it was not possible to measure theforce required for detachment. Surprisingly, the formed patternednonwoven fabric did not stick to the base during the hydroentanglement.No fibres were either seen by the visual inspection been attached tothis kind of a patterned, perforated metal plate.

1: A method for patterning nonwoven fabric, including steps in thefollowing order forming of one or a plurality of fibre webs, patterningof the fibre web or combined fibre webs by hydroentanglement, drying ofthe nonwoven fabric, characterized in that during the said patterningstep, the web is supported on a perforated plate in a cylinder form (23,23′), to which cylinder has been formed by embossing a three-dimensionalpattern or patterns which are provided with orifices (30) of the saidplate (pattern cylinder), and that in said patterning byhydroentanglement, pattern or patterns substantially corresponding tothe 3-dimensional pattern or patterns (32) of the pattern cylinderis/are obtained in the nonwoven fabric. 2: A method in accordance withclaim 1, characterized in that in the patterning by hydroentanglementsubstantially only the pattern or patterns corresponding to the3-dimensional pattern or patterns (32) embossed to the pattern cylinder(23, 23′) is/are obtained in the nonwoven fabric. 3: A method inaccordance with claim 1, characterized in that the opacity of thenonwoven fabric at the said pattern or patterns is on average lower thanat non-patterned portion of the nonwoven fabric. 4: A method inaccordance with claim 1, characterized in that the grammage of thenonwoven fabric at the said pattern or patterns is on average lower thanthat of the non-patterned portion of the nonwoven fabric. 5: A method inaccordance with claim 1, characterized in that at least one fibre web isformed by carding. 6: A method in accordance with claim 1, characterizedin that at least one fibre web is prebonded before the patterning. 7: Amethod in accordance with claim 1, characterized in that the fibre webor the fibre webs are prebonded mechanically, especially byhydroentangling. 8: A method in accordance with claim 1, characterizedin that the fibres to be used are stable fibres. 9: A method inaccordance with claim 1, characterized in that a composite ofpolypropylene or polyester fibres and viscose fibres is used. 10: Amethod in accordance with claim 9, characterized in that in the fibremixture the mass portions polypropylene: viscose or polyester: viscoseare ranging from 20:80 to 80:20. 11: An apparatus for patterningnonwoven fabric, said apparatus comprising an element for supporting theweb, a vacuum system and water nozzles (25) for patterning the fibre webor the combined fibre webs by hydroentanglement, characterized in thatthe element for supporting the web is a perforated plate, in the form ofa cylinder, having a three-dimensional pattern or patterns (32) formedonto it by embossing (pattern cylinder) in order to obtain patterns inthe nonwoven fabric and that the pattern or patterns in the patterncylinder are provided with orifices (30) of the said plate. 12: Anapparatus in accordance with claim 11, characterized in that the surface(31) of the pattern cylinder that has not been formed by embossing,forms a plane level of the plate surface from which surface the3-dimensional pattern or patterns (32), formed by embossing, protrudeupwards, downwards or to both directions. 13: An apparatus in accordancewith claim 11, characterized in that said pattern cylinder comprises oneor of a plurality of perforated plates. 14: An apparatus in accordancewith claim 11, characterized in that the apparatus comprises a honeycombstructure (21) and a pattern cylinder (23) is adapted directly onto thehoneycomb construction. 15: An apparatus in accordance with claim 11,characterized in that a support cylinder (22′) is arranged between thepattern cylinder (23′) and the honeycomb structure (21′). 16: Anapparatus in accordance with claim 11, characterized in that thediameter of the orifices (30) of the pattern cylinder ranges from 0.2 to3.0 mm, preferably from 0.2 to 1.0 mm. 17: An apparatus in accordancewith claim 11, characterized in that the distance of the orifices of thepattern cylinder from each other is at least 0.5 mm, preferably from 1to 1.5 mm. 18: An apparatus in accordance with claim 11, characterizedin that the portion of the perforated surface area of the patterncylinder ranges from 8 to 50%, preferably from 8 to 22%. 19: Anapparatus in accordance with claim 11, characterized in that theorifices of the pattern cylinder are arranged regularly, especially internary (triangle) distribution. 20: An apparatus in accordance withclaim 11, characterized in that the difference between the bottom andthe peak of the pattern in the pattern cylinder is from 1 to 3 mm,preferably 1.5 mm. 21: An apparatus in accordance with claim 11,characterized in that the cross-section of the orifices of the patterncylinder is substantially round. 22: Use of an apparatus in accordancewith claim 11 in the patterning step in accordance with a method forpatterning nonwoven fabric, including steps in the following orderforming of one or a plurality of fibre webs, patterning of the fibre webor combined fibre webs by hydroentanglement, drying of the nonwoven web,characterized in that during the said patterning step, the web issupported on a perforated plate in a cylinder form (23, 23′), to whichcylinder has been formed by embossing a three-dimensional pattern orpatterns which pattern or patterns coincide with orifices (30) of thesaid plate (pattern cylinder), and that in said patterning byhydroentanglement pattern or patterns substantially corresponding to the3-dimensional pattern or patterns (32) embossed to the pattern cylinderare accomplished to the nonwoven fabric.